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Chapter 12 Part Two: Systematics: The Science of Biological Diversity. Development of classification. A. Until relatively recently organisms were classified as either plants or animals and two kingdoms were recognized. 1. Non-motile autotrophs were placed in the plant kingdom
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Chapter 12 Part Two: Systematics: The Science of Biological Diversity
Development of classification • A. Until relatively recently organisms were classified as either plants or animals and two kingdoms were recognized. • 1. Non-motile autotrophs were placed in the plant kingdom • 2. Motile heterotrophs were placed in the animal kingdom
Many organisms didn’t fit 1. Euglena is a unicellular, motile autotroph 2. Fungi (mushrooms and molds), traditionally classified as plants, are non-motile heterotrophs
Technology led to better classifying cells 1. Prokaryotes (bacteria) - lack: nuclei, organelles, flagella, chromosomes, multicellularity and sexuality 2. Eukaryotes (nearly all other organisms) - have: nuclei, organelles, flagella, DNA associated with histone proteins to form chromatin/chromosomes, sexual reproduction and most are multicellular
Thomas Whitaker (1969) 5 kingdom system All Prokaryotes were placed into a single kingdom (Monera i.e. bacteria) and the Eukaryotes were placed into four kingdoms: Plantae, Fungi, Animalia and Protista (unicellular)
Three domains A. Recent genetic and molecular investigations have demonstrated that there are two major groups of prokaryotes. They differ radically in the composition of their cell walls, membrane lipids, ribosomal RNA, and a variety of other biochemical features
Therefore, our text recognizes three domainsabove the rank of kingdom
1. Domain Bacteria - prokaryotes with muramic acid in cell walls. Majority of bacteria plus cyanobacteria ("blue green algae")
2. Domain Archaea (ancient bacteria) - prokaryotes that lack muramic acid in cell walls. Many inhabit "harsh" environments. Includes methane producers, extreme halophiles, extreme thermophiles, acidophiles and one group which lacks cell walls
3. Domain Eukarya • all eukaryotes, four kingdoms: • Animalia • Plantae • Fungi • Protista
Kingdom Animalia (Animals) - motile, multicellular, lack plastids and cell walls, heterotrophic via ingestion, sexual reproduction
Kingdom Plantae (Plants) - nonmotile, multicellular, plastids and autotrophic via photosynthesis, cell walls made of cellulose, adapted for life on land, mostly sexual reproduction. "Algae" are not included in this kingdom
Kingdom Fungi (Mushrooms and Molds) - nonmotile, filamentous, lack plastids, cell walls are made of chitin, heterotrophic via absorption of nutrients from dead (saprophytic) or living (parasitic) matter. Virtually all are multicellular except yeast. Both sexual and asexual reproduction
Kingdom Protista - lack multicellularity. Heterogeneous assemblage of unicellular, colonial and multicellular Eukaryotes that do not have the distinctive characters of plants, animals or fungi. • They have various types of reproduction from simple cell division through sexual, and various types of nutrition • Includes all groups previously called protozoa as well as all the algae except blue greens. Also includes some organisms previously called fungi
Origin of a Photosynthetic eukaryotic cell from a heterotrophic prokaryote
Autotrophic endosymbiotic alga Electron Micrograph of a Vorticella
Fungi • Lichen • Fungus • mushroom
Fungi- red blanket lichen Florida swamp
White coral fungus Clavariacea
Mushrooms genus Mycena Rainforest Peru
Earthball Scleroderma citrinum
Protist • Plasmodium slime mold • Postelsia palmiformis- “sea palm” • Volvox- green alga • Fauchea- red alga • Pennate diatom
Plants Three phyla of bryophytes • Sphagnum (peat moss) • Marchantia (thallose liverworts) • Club moss Seven phyla of vascular plants • Wood Horsetail • Maidenhair fern • Dandelion Taraxacum officinale • Strawberry cactus • Foxtail barley • Cymbidium orchids • Sugar pine
Bryophytes Sphagnum (peat moss)